After finishing his meal, my cat will often grab a paper towel, piece of newspaper or some other light object and cover his remaining food with it. Why does he do this? Does it mean he didn’t like the food?

The behavior you describe is quite common. A cat gobbles up his meal but leaves behind a few leftovers. Instead of just walking away, he then covers up the food with something, as you wrote. Some cats will even try to bury the food, pawing at it if the food is on something flexible. Not all cats exhibit this behavior, but many do.
What appears to be a sad burial is actually more of a “camouflage.” Cats in the wild often cover partially eaten meals so they can return to them later. The cover-up also helps mask the food’s appearance and scent, both of which could lure predators and competitors. Your kitty’s habit therefore may have deep, ancestral roots.
To prevent your cat from covering its food, place your feline’s food in a sturdy bowl away from loose papers. Only provide recommended portions so as to not have too many leftovers.